Hydraulic damping and stabilizing device



Mam 14, 1944. A, A MQRTON 2,344,050

HYDRAULIC DAMPING AND STABILIZING DEVICE March 14, 1944. A, A MOTQN2,344,650

HYDRAULIC DMPING AND STABILIZING DEVICE* Filed June 5, 1941 2Sheets-Sheet 2 Patented Mar. 14, i944 HYDRAULIC DIWPIN G AND STABILIZINGDEVICE Andr Adolphe Morton,

the Alien Prop Paris, France; vested in erty Custodian Application June5, 1941, Serial No. 396,778 In France May 9, 1940 3 Ciaims.

In the French Patent 855,043, filed January 17, 1939, by Paul HenryMistral, is described a suspension gear for motor vehicles, in whichbetween the suspended and nonsuspended part of the Vehicle are arrangedtwo pairs of hydraulic devices located respectively at the front andrear of the vehicle and hydraulically connected to one another, in eachpair, by crossed pipings so that the motion of the movable part of onedevice sets up a movementof the same amount and in the same direction orthe movable part of the other device.

This system acts as a stabilizing and damping device for the suspensionand comprises:

(a) A device compensating the expansions and contractions of the liquid,and

(b) An adjustable valve for the damping, which sets up a paralleladjustment of the suspension and damping.

During tests made after connection of maximum recording pressure gaugeson the various pipings, the following facts have been obselved:

l. The pressures involved in the stabilizing action are considerablylower than those occurring during damping,

2. The damping pressures are much lower at high speed than at low speed,viz., oi the order of 350 kg./sq. cm. at 80 lim/hr. against 600 lig/sq.cm. at 4() km./hr., and

3. The stabilization of small oscillations is highly straining for thevehicle frame'now used on the majority of cars. v

From these facts it may be deduced that there is a certain interest innot stabilizing small oscillations, but only damping them out, the limitbetween these two loperations may be ad-` justed diierently for the foreand aft of the vehicle, i. e., with respect to the position of the masscentre on the longitudinal axis of said vehicle.

The object of the present invention is a damp ing and stabilizing deviceadapted to fulll the above conditions and, for the purpose of il1ustration, an embodiment of the apparatus according to the invention will bedescribed below,'by wayl of example, with reference to ings, in which:

Figure 1 shows in the rest position thedamping the joined drawandstabilizing device according to the invention,

in longitudinal vertical section along the axis, Figures 2 and 3 arevertical transverse sections respectively along the lines 2 2 and 3-3 ofFigure 1, and

Figure 4 shows diagrammatically and at a smaller scale the front of amotor vehicle tted ybe with two hydraulic devices of the sameconstruction as that shown in Figures 1 to 3.

As shown in Figure 4, the damping and stabiliz ing device according tothe invention, adapted to fitted either to the front wheels, as shown,or to the back wheels of a motor vehicle, comprises two similarhydraulic devices A and A1, connected to one another as explained below,by two transverse pipes B, B1, while suitable connecting rods connectthe movable part of the devices to the nonsuspended part of the vehicle.

In Figures l to 3 each hydraulic device comrises a body l comprising inits central part a chamber 2 constituting an oil reserve tank and closedhermetically at its upper part by a lid t with a gasketl.

This hollow body further comprises two circular bores of the same ordifferent diameters, divided each by chamber 2 into spaced portionsconstituting two cylinders referred to respectively as 5, 5a for theupper, and E, tia for the lower.

Inside the cylinders 5, 5a, closed, at their ends, by plugs 'i' and 7a,is mounted slidably in both directions a piston 8 which may be providedin addition, as shown, with sealing devices such as leather cups 9, 9a.

In the example shown, the piston 8 is connected, by a block It, to alever arm H keyed to a shaft l2 rotatable in the bearings i3 of' thehollow body l and connected by a connecting'rod I5 or any other suitablepart, to the axle I5, asshown in Figure 4.

The movements of piston 8 are thus controlled by the oscillationsimpressed to the axle i6 during the travel of the vehicle, the pistonmoving at'the same time as the axle or the part replacing the latterv inthe case of independent wheels.

In the lower cylinders 6, 6a is movable a second piston Il, lla,provided at its ends with packings such as leather cups I3, 13a, andcom# prising'stops I9,H|9c These two cylinders 6, 6a are closedrespectively by plugs 2t, Zta, the first of which carries a stop stud2lV of a non-soundproducing substance, andthe second a stop 22 providedwith asimilar stop stud 2 la.

The pistonl ll, Ila is brought .into Contact with the stud 2 i, as shownin Figure. 1 by a spring 23, the tension of which is such that it Vmayonly overcome the sliding resistance `o1 said piston in the cylinders 6,avduring .the idle periodsof pis-- its travel. Y

At rest, with the piston l1, lia 'each ofV the two apparatus A, A1located at the front carrying an outer lever lll consequently,

the idle periods of piston 8 and during the stops of the vehicle, arenormally maintained by their of box 29 and in the central bore of whichthe stem 31 of the needle is mounted vertically slidable and maintainedagainst any angular displacement by the ring 38 in a vertical groove 42of which is freely engaged a screw 43 fixed in the box 29.

For giving the needle 39 the required vertical Y displacements and thusvarying the cross section of the annular passage formed between-saidneedle and the central aperture 3| of the washer l. 32, as explained,the shaft 4| carrying the helical weight in the open position as shownin Figure V' l, and set up communication between the oil reserve tank 2and the cylinders 5, 5a over chan-- nels 2B, 23a and the valve seats 25,25a.n

Cylinder 5 further communicates, asA seen in A Y Figure 3, with.cylinder 6 by means of twoV channels 21, A28 leading,V the first, intothe upper part, and the second into the lower part of a box 29 insidewhich is arranged a needle valve 30 adapted to be moved vertically andto penetrate more or less intothe central conical aperture/3| of awasherV 32in order to Vadjustthe cross-'sectionv ofthe annularfp'assageformed between said aperture 3| and the point of the needle valve, andsetting 'into communication with one another the twofchannels 21, 28vand, both cylinders 5 and 6. The two cylinders ofachannel 33o drilledinto 'the wall common t0 both cylinders, as seen in Figure 1.1

i The two lower cylinders' 6,6a ofeach ofthe two apparatusy A, Ai inFigure 4 areV provided with two nipples 34, 34a arrangedrespectively toone another as shown in Figure "4, and to which Aare connected two pipesB, Bi connecting both apparatus A, Ai of the 'frontcr rear f thevehicle-in such a manner thatthe nippley 34 of the left apparatus'Abeconnected to nipple 34d of the right apparatus' Ai, whilebnipple 34 ofthe'right VapparatusAi is connected'to'nippleV 34a ofthe left apparatusA.

Due to this arrangement,l the central oil reserve -tank 2 of each deviceA, Ai communicates withv the bores` or cylinders 5, 5a which commu-Vnicate with' the bores or cylindersi, 6a, so that all these cylindersand both crossed-pipes B, Bi connecting ,the tvvo devicesV d 5a and (ittare" constantly` in communication withv one another by lmeans Ai, asdescribed Vments of the required direction and ramp 40 is connected, bymeans of a crank 44 keyed toV said shaft, to a suitable control deviceallowing the driver of the vehicle to give from a distance to said shaft4| angular displaceamplitude forl obtaining, byV means of the helicalramps #1D-'and 39 a lift or adownward motion of the needle 30 and forpermitting, as will be explained,

a damping of the small oscillations, and conibined damping andstabilization of oscillations Aof larger amplitude.

The operation ofthe apparatus described above v is as follows:

may happen that piston Each-of the 'vaives zit, zsafis meantto com: Y

pensate the expansions and contract-ionsfof the"` liquid under, theeffect of Vvariations off the fouter temperature' or ofthe'temperature'of 'the liquid,

by the displacements'V impressed vonrpistonl byY the-oscillationstransmittedto the vehcle'rby road bumps. A i

or cylinders '5` men ` 6o is thus moved to' Athe 'The'needle V3i)interposedbetween theA bores"V andA 6 of each 'deViceA,j"Ai-, 'con-Jtrolling the communication'between them,is` `inf serted,'as explainedabove, inthe centralconical aperture 3| of a washer 32 .which,undernormal conditions, ismaintained applied against an inner nange of-box 29by a light-spring 35 inserted with the-needle. Y 1 .1.; Y

The stem 31 of `needle 3|! carries,xedto the latter below'thejcollar 33,aring 38, the lower base of which formsv a helical ramp 3.9 maintainedincontact by a spring with anotherl helical ramp 49 formed at the upperend of a vertical hollowshaft ,trotating insideV the bodyv vbetweensaidwasher y:32v and a collar l33 integral i When, owing to road bumps,piston 8, Figure 1, is moved in cylinder 5 towardsr the left of thisfigure, the liquid, carried along in this movement, rst closes the valve25 and is then discharged throughV the channel 21 into box 29 of valve 3and through channel 28 into cylinder 15.n Since piston I1 Vis subjectedonly to the light resistance of spring 23, it will'be pushed towards theright, thereby discharging into cylinder 6a, under the push of piston|1a integral with |1, an amount of liquid equal to'that entered intocylinder 6. This liquid will enter,'thr'ough channel 33a, into cylinder6a and thus iill the space cleared in cylinder 5a by the'motion ofpiston towards the left.

If the' movement of piston 8 is only small, it '|1, |1a be moved to theright only by an amount equal at most to the distance separating theYstop |9a from the stud 2|a; in this case, the device will operate onlyon one side of the vehicle. i

Upon return of piston 8 towards the right, i. e., after the roadhump hasbeen passed, the liquid is delivered by saidb piston of cylinder 5a intocylinder 6a, piston ||a,v moves, in turn, towards theleft andpiston |1integral with |1a discharges an equal vamount of liquid into cylinder 5over valve 33 which produces theudamping Aeffrect for which it'has been`adjusted. Y If, yon the contrary, pistonfis moved by a large amounttowards the left, it will discharge,

lilrst into cylinder l i5,V an amount of4 liquid equal to themaximumrpermitted bythe space separating the stop Ida from stud 2 la;piston |1, |1a y ri'ght of Figure 1 and stopped, at the end of itsstroke, by the abutment, of stopA |,9a against lstud 2Ia, so that theexcessof liquid d ischar'gedby piston 8 in suc-` cession into cylinder 5and cylinder 6 will escape from thelatter throughy nipple 34, Figures 1,3

and 4, and Vbe discharged from saidicylinder 6 of one of the apparatus,A for instance, Figure 4, into the corresponding cylinder BaifapparatusAi,y through the pipe .B and'nipplefv 34a asl seen 'With the piston |1-of-thissecond apparatus `Ai locked-by its stop v|9whichis in contactwith stud 2|, the liquid then -passes through channel 33o into cylinder5a of said apparatus Ai, thereby repelling piston 8, which,rby Vitsother face,

discharges liquid from cylinder into cylinders 5a and 5a of the rstapparatus A through the nipple S4, pipe B1 and nipple iria of saidapparatus A.

It will be seen that these various movements set; up: the rst action ofclosing one or other of the compensating valves 25, a, the second actionof damping out alone the small oscillations, and lastly the third actionof combined stabilizing and damping of the larger oscillations.

The described arrangements are, of course, indicated only by way ofexample, the shapes, substances and dimensions of the elementsconstituting the damping and stabilizing apparatus, and theconstructional details may be modied without departing from the presentinvention.

What I claim is:

1. In a stabilizing and damping system of the type described, forvehicles comprising a suspended and a nonsuspended part, in combination,at least two similar` hydraulic devices arranged on either side of thelongitudinal axis of the vehicle and comprising each a hollow bodyforming an oil tank in its central part and provided with twoboresforming two superposed cylinders, means connecting this hollow body tothe suspended part of the Vehicle, a movable piston in the first of saidcylinders, means connecting this piston to the nonsuspended part of thevehicle, connections connecting the outer chambers of the other of saidcylinders, two by two and orosswise, with the outer chambers of thecorresponding cylinder of the other hydraulic device, said body havingchannel connections connecting the outer chambers or the rst oi saidcylinders with the second of said cylinders, an adjustable damping valvein the last mentioned connections, stops provided on the bottoms of thesecond of said cylinders, a closing piston sliding in the bore of thesecond of said cylinders, stops provided on the ends of said closingpiston and adapted to come into contact respectively with one or theother stop of said second cylinder according as to whether the suspendedpart and the nonsuspended part of the vehicle remain xed with respect toone another or move relatively to one another with an amplitude greaterthan a predetermined value, two compensating valves respectivelyconnecting the outer chambers of the iirst of said cylinders with saidoil tank, and of which one or the other is adapted to stop thisconnection according to the direction of movement of the suspended partwith respect to the nonsuspended part of the vehicle.

2. In a stabilizing and damping system of the type described, forvehicles comprising a suspended and a nonsuspended part, in combination,at least two similar hydraulic devices arranged on either side of thelongitudinal axis of the vehicle and comprising each a hollow bodyforming an oil tank in its central part and provided vvith two boresforming two superposed cylinders, means connecting this hollow body tothe suspended part of the vehicle, a movable piston in the rst of saidcylinders, means connecting this piston to the nonsuspended part of thevehicle, connections connecting the outer chambers of the other of saidcylinders, two by two and crosswise, with the outer chambers of thecorresponding cylinder of the other hydraulic device, said body havingchannel connections connecting the outer chambers of the first of Saidcylinders with the second of said cylinders, and adjustable dampingvalve in the last mentioned connections, stops provided on the bottomsof the second of said cylinders, fittings in a sound proof substancemounted on these stops, a closing piston sliding in the bore of thesecond of said cylinders, stops provided on the ends of said closingpiston and adapted to come into contact respectively with one or theother stop oi' said second cylinder according as to whether thesuspended part and the nonsuspended part of the vehicle remain iiXedwith respect to one another or move relatively to one another with anamplitude greater than a predetermined value, two compensating valvesrespectively connecting the outer chambers of the first of saidcylinders with said oil tank, and of which one or the other is adaptedto stop this connection according to the direction of movement of thesuspended part with respect to the noneuspended part of the vehicle.

3. In a stabilizing and damping system of the type described, forvehicles'comprising a suspended and a nonsuspended part, in combination,at least two similar hydraulic devices arranged on either side or thelongitudinal axis of the vehicle and comprising each a hollow bodyforming an oil tank in its central part and provided with two boresforming two superposed cylinders, means connecting this hollow body tothe suspended part of the vehicle, a movable piston in the irst of saidcylinders, means connecting this piston to the nonsuspended part oi thevehicle, connections connecting the outer chambers of the other of saidcylinders, two by two and crosswise, with the cuter chambers of thecorresponding cylinder of the other hydraulic device, said body havingchannel connections connecting the outer chambers of the first of saidcylinders with the second of cylinders, an adjustable damping valve inthe last mentioned connections, stops provided on the bottoms of thesecond of said cylinders, a closing piston sliding in the bore of thesecond of said cylinders, stops provided on the ends of said closingpiston and adapted to come into contact respectively with one or theother stop of said second cylinder according as to whether the suspendedpart and the nonsuspended part of the vehicle remain xed with respect toone another or move relatively to one another with an amplitude greaterthan a predetermined value, elastic means inserted between one of thebottoms of said second cylinder and the end opposite said closing pistonand the elastic force of which is suicient only for displacing saidclosing piston, when the suspended and nonsuspended parts of the vehicleare unmovable with respect to one another, in order to bring intocontact the stop of the other end of the closing piston with thecorresponding stop of the other bottom of said second cylinder, twocompensating valves respectively connecting the outer chambers of theiirst of said cylinders with said oil tank, and of which one or theother is adapted to stop this connection according to the direction ofmovement of the suspended part with respect to the nonsuspended part ofthe Vehicle.

ANDRE' ADOLPHE MoR'roN.

